نتایج جستجو برای: surface soil

تعداد نتایج: 797336  

2000
F. Graef K. Stahr

Soil water availability is most essential in the Sahelian agriculture but is hampered by several factors. Surface crusts or crust-like surfaces, which are characteristic of most Sahelian soils, have been shown to decrease water in®ltrability and increase runoff. Their type and structure are in ̄uenced by soil texture, vegetation cover, erosion and deposition effects of wind and water. A soil and...

2002

Acid soil covers one third of the world arable lands. Excess Al and H in acid soil are not favorable for most plants. Calcium carbonates and gypsum (CaSO4) are used to improve chemical status of the acid soil. However, application of Ca cation may sometimes enhance dispersion and deteriorate soil physical properties. Presenting study discusses effect of non-ionic polyacrylamide (PAM) applicatio...

2009
Kaijun Song Xiaobing Zhou Yong Fan

A multilayer soil model is presented for improved estimation of soil moisture content using the first-order small perturbation method (SPM) applied to measurements of radar backscattering coefficient. The total reflection coefficient of the natural bare soil including volume scattering contribution is obtained using the multilayer model. The surface reflection terms in SPM model are replaced by...

2011
Tiago Zschornack Cimélio Bayer Josiléia Acordi Zanatta Frederico Costa Beber Vieira

Winter cover crops are sources of C and N in flooded rice production systems, but very little is known about the effect of crop residue management and quality on soil methane (CH4) and nitrous oxide (N2O) emissions. This study was conducted in pots in a greenhouse to evaluate the influence of crop residue management (incorporated into the soil or left on the soil surface) and the type of cover-...

2007
R. van der Velde M. D. van Helvoirt

This paper reports on the comparison of surface temperature and soil moisture observed by instruments onboard the Environmental Satellite (EnviSat) with simulations by an atmospheric circulation model over the period April 2005 to September 2007. The Naqu river basin has been selected as the study area, which is located on the eastern part of Tibetan Plateau. For the selected period, the PSU/NC...

2008
Gilles Valette Stéphanie Prévost Laurent Lucas Joël Léonard

We aim to model and visualize the evolution of the surface structure of a cultivated soil surface during rainfall. In this paper, we briefly present our model, based on an Extended Cellular Automaton, and the different simulated processes. Among these processes, we focus on runoff which is of high relevance as it drives the evolution of the soil surface structure by transporting anddepositing t...

2016
Wenjun Ji Mi Lin Asim Biswas Bing C. Si Henry W. Chau Hamish P. Cresswell

Spatiotemporal behavior of soil water is essential to understand the science of hydrodynamics. Data intensive measurement of surface soil water using remote sensing has established that the spatial variability of soil water can be described using the principle of self-similarity (scaling properties) or fractal theory. This information can be used in determining land management practices provide...

2010
K. J. Song X. B. Zhou

A multilayer soil model for retrieving soil moisture content using the Integral Equation Method (IEM) is investigated in this paper. The total reflection coefficients of the natural soil are obtained using the multilayer model, and volumetric scattering is approximated by the internal reflections between layers. The surface reflection terms in IEM model are replaced by the total reflection coef...

Journal: :Annals of botany 2007
M D Cramer C Kleizen C Morrow

BACKGROUND AND AIMS A test was made of the hypothesis that the prostrate growth habit of the leaves of the geophyte Brunsvigia orientalis enables utilization of soil-derived CO(2) and is related to the presence of lysigenous air-filled channels characteristic of B. orientalis leaves. METHODS Brunsvigia orientalis was sampled at a field site. Leaf anatomy, stomatal density, leaf/soil gas excha...

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